You might have to re-add the locals. I think the following steps will return your OTA locals on the 612.
1. Turn off 612
2. Hook up your OTA antenna to the 612
3. Turn on 612 and TV
4. On the Remote, Press Menu, Installation, Local Channels (8)
5. From the Locals Menu, select Scan
6. After Scan is complete, select Save/Ok
The locals should now be added to your Guide.
Good Luck,
Bob